1 files changed, 408 insertions, 0 deletions
diff --git a/www/wiki/includes/media/DjVuImage.php b/www/wiki/includes/media/DjVuImage.php
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+++ b/www/wiki/includes/media/DjVuImage.php
@@ -0,0 +1,408 @@
+<?php
+/**
+ * DjVu image handler.
+ *
+ * Copyright © 2006 Brion Vibber <brion@pobox.com>
+ * https://www.mediawiki.org/
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ * @ingroup Media
+ */
+
+/**
+ * Support for detecting/validating DjVu image files and getting
+ * some basic file metadata (resolution etc)
+ *
+ * File format docs are available in source package for DjVuLibre:
+ * http://djvulibre.djvuzone.org/
+ *
+ * @ingroup Media
+ */
+class DjVuImage {
+	/**
+	 * @const DJVUTXT_MEMORY_LIMIT Memory limit for the DjVu description software
+	 */
+	const DJVUTXT_MEMORY_LIMIT = 300000;
+
+	/**
+	 * @param string $filename The DjVu file name.
+	 */
+	function __construct( $filename ) {
+		$this->mFilename = $filename;
+	}
+
+	/**
+	 * Check if the given file is indeed a valid DjVu image file
+	 * @return bool
+	 */
+	public function isValid() {
+		$info = $this->getInfo();
+
+		return $info !== false;
+	}
+
+	/**
+	 * Return data in the style of getimagesize()
+	 * @return array|bool Array or false on failure
+	 */
+	public function getImageSize() {
+		$data = $this->getInfo();
+
+		if ( $data !== false ) {
+			$width = $data['width'];
+			$height = $data['height'];
+
+			return [ $width, $height, 'DjVu',
+				"width=\"$width\" height=\"$height\"" ];
+		}
+
+		return false;
+	}
+
+	// ---------
+
+	/**
+	 * For debugging; dump the IFF chunk structure
+	 */
+	function dump() {
+		$file = fopen( $this->mFilename, 'rb' );
+		$header = fread( $file, 12 );
+		$arr = unpack( 'a4magic/a4chunk/NchunkLength', $header );
+		$chunk = $arr['chunk'];
+		$chunkLength = $arr['chunkLength'];
+		echo "$chunk $chunkLength\n";
+		$this->dumpForm( $file, $chunkLength, 1 );
+		fclose( $file );
+	}
+
+	private function dumpForm( $file, $length, $indent ) {
+		$start = ftell( $file );
+		$secondary = fread( $file, 4 );
+		echo str_repeat( ' ', $indent * 4 ) . "($secondary)\n";
+		while ( ftell( $file ) - $start < $length ) {
+			$chunkHeader = fread( $file, 8 );
+			if ( $chunkHeader == '' ) {
+				break;
+			}
+			$arr = unpack( 'a4chunk/NchunkLength', $chunkHeader );
+			$chunk = $arr['chunk'];
+			$chunkLength = $arr['chunkLength'];
+			echo str_repeat( ' ', $indent * 4 ) . "$chunk $chunkLength\n";
+
+			if ( $chunk == 'FORM' ) {
+				$this->dumpForm( $file, $chunkLength, $indent + 1 );
+			} else {
+				fseek( $file, $chunkLength, SEEK_CUR );
+				if ( $chunkLength & 1 == 1 ) {
+					// Padding byte between chunks
+					fseek( $file, 1, SEEK_CUR );
+				}
+			}
+		}
+	}
+
+	function getInfo() {
+		Wikimedia\suppressWarnings();
+		$file = fopen( $this->mFilename, 'rb' );
+		Wikimedia\restoreWarnings();
+		if ( $file === false ) {
+			wfDebug( __METHOD__ . ": missing or failed file read\n" );
+
+			return false;
+		}
+
+		$header = fread( $file, 16 );
+		$info = false;
+
+		if ( strlen( $header ) < 16 ) {
+			wfDebug( __METHOD__ . ": too short file header\n" );
+		} else {
+			$arr = unpack( 'a4magic/a4form/NformLength/a4subtype', $header );
+
+			$subtype = $arr['subtype'];
+			if ( $arr['magic'] != 'AT&T' ) {
+				wfDebug( __METHOD__ . ": not a DjVu file\n" );
+			} elseif ( $subtype == 'DJVU' ) {
+				// Single-page document
+				$info = $this->getPageInfo( $file );
+			} elseif ( $subtype == 'DJVM' ) {
+				// Multi-page document
+				$info = $this->getMultiPageInfo( $file, $arr['formLength'] );
+			} else {
+				wfDebug( __METHOD__ . ": unrecognized DJVU file type '{$arr['subtype']}'\n" );
+			}
+		}
+		fclose( $file );
+
+		return $info;
+	}
+
+	private function readChunk( $file ) {
+		$header = fread( $file, 8 );
+		if ( strlen( $header ) < 8 ) {
+			return [ false, 0 ];
+		} else {
+			$arr = unpack( 'a4chunk/Nlength', $header );
+
+			return [ $arr['chunk'], $arr['length'] ];
+		}
+	}
+
+	private function skipChunk( $file, $chunkLength ) {
+		fseek( $file, $chunkLength, SEEK_CUR );
+
+		if ( $chunkLength & 0x01 == 1 && !feof( $file ) ) {
+			// padding byte
+			fseek( $file, 1, SEEK_CUR );
+		}
+	}
+
+	private function getMultiPageInfo( $file, $formLength ) {
+		// For now, we'll just look for the first page in the file
+		// and report its information, hoping others are the same size.
+		$start = ftell( $file );
+		do {
+			list( $chunk, $length ) = $this->readChunk( $file );
+			if ( !$chunk ) {
+				break;
+			}
+
+			if ( $chunk == 'FORM' ) {
+				$subtype = fread( $file, 4 );
+				if ( $subtype == 'DJVU' ) {
+					wfDebug( __METHOD__ . ": found first subpage\n" );
+
+					return $this->getPageInfo( $file );
+				}
+				$this->skipChunk( $file, $length - 4 );
+			} else {
+				wfDebug( __METHOD__ . ": skipping '$chunk' chunk\n" );
+				$this->skipChunk( $file, $length );
+			}
+		} while ( $length != 0 && !feof( $file ) && ftell( $file ) - $start < $formLength );
+
+		wfDebug( __METHOD__ . ": multi-page DJVU file contained no pages\n" );
+
+		return false;
+	}
+
+	private function getPageInfo( $file ) {
+		list( $chunk, $length ) = $this->readChunk( $file );
+		if ( $chunk != 'INFO' ) {
+			wfDebug( __METHOD__ . ": expected INFO chunk, got '$chunk'\n" );
+
+			return false;
+		}
+
+		if ( $length < 9 ) {
+			wfDebug( __METHOD__ . ": INFO should be 9 or 10 bytes, found $length\n" );
+
+			return false;
+		}
+		$data = fread( $file, $length );
+		if ( strlen( $data ) < $length ) {
+			wfDebug( __METHOD__ . ": INFO chunk cut off\n" );
+
+			return false;
+		}
+
+		$arr = unpack(
+			'nwidth/' .
+			'nheight/' .
+			'Cminor/' .
+			'Cmajor/' .
+			'vresolution/' .
+			'Cgamma', $data );
+
+		# Newer files have rotation info in byte 10, but we don't use it yet.
+
+		return [
+			'width' => $arr['width'],
+			'height' => $arr['height'],
+			'version' => "{$arr['major']}.{$arr['minor']}",
+			'resolution' => $arr['resolution'],
+			'gamma' => $arr['gamma'] / 10.0 ];
+	}
+
+	/**
+	 * Return an XML string describing the DjVu image
+	 * @return string|bool
+	 */
+	function retrieveMetaData() {
+		global $wgDjvuToXML, $wgDjvuDump, $wgDjvuTxt;
+
+		if ( !$this->isValid() ) {
+			return false;
+		}
+
+		if ( isset( $wgDjvuDump ) ) {
+			# djvudump is faster as of version 3.5
+			# https://sourceforge.net/p/djvu/bugs/71/
+			$cmd = wfEscapeShellArg( $wgDjvuDump ) . ' ' . wfEscapeShellArg( $this->mFilename );
+			$dump = wfShellExec( $cmd );
+			$xml = $this->convertDumpToXML( $dump );
+		} elseif ( isset( $wgDjvuToXML ) ) {
+			$cmd = wfEscapeShellArg( $wgDjvuToXML ) . ' --without-anno --without-text ' .
+				wfEscapeShellArg( $this->mFilename );
+			$xml = wfShellExec( $cmd );
+		} else {
+			$xml = null;
+		}
+		# Text layer
+		if ( isset( $wgDjvuTxt ) ) {
+			$cmd = wfEscapeShellArg( $wgDjvuTxt ) . ' --detail=page ' . wfEscapeShellArg( $this->mFilename );
+			wfDebug( __METHOD__ . ": $cmd\n" );
+			$retval = '';
+			$txt = wfShellExec( $cmd, $retval, [], [ 'memory' => self::DJVUTXT_MEMORY_LIMIT ] );
+			if ( $retval == 0 ) {
+				# Strip some control characters
+				$txt = preg_replace( "/[\013\035\037]/", "", $txt );
+				$reg = <<<EOR
+					/\(page\s[\d-]*\s[\d-]*\s[\d-]*\s[\d-]*\s*"
+					((?>    # Text to match is composed of atoms of either:
+						\\\\. # - any escaped character
+						|     # - any character different from " and \
+						[^"\\\\]+
+					)*?)
+					"\s*\)
+					| # Or page can be empty ; in this case, djvutxt dumps ()
+					\(\s*()\)/sx
+EOR;
+				$txt = preg_replace_callback( $reg, [ $this, 'pageTextCallback' ], $txt );
+				$txt = "<DjVuTxt>\n<HEAD></HEAD>\n<BODY>\n" . $txt . "</BODY>\n</DjVuTxt>\n";
+				$xml = preg_replace( "/<DjVuXML>/", "<mw-djvu><DjVuXML>", $xml, 1 );
+				$xml = $xml . $txt . '</mw-djvu>';
+			}
+		}
+
+		return $xml;
+	}
+
+	function pageTextCallback( $matches ) {
+		# Get rid of invalid UTF-8, strip control characters
+		$val = htmlspecialchars( UtfNormal\Validator::cleanUp( stripcslashes( $matches[1] ) ) );
+		$val = str_replace( [ "\n", '�' ], [ '&#10;', '' ], $val );
+		return '<PAGE value="' . $val . '" />';
+	}
+
+	/**
+	 * Hack to temporarily work around djvutoxml bug
+	 * @param string $dump
+	 * @return string
+	 */
+	function convertDumpToXML( $dump ) {
+		if ( strval( $dump ) == '' ) {
+			return false;
+		}
+
+		$xml = <<<EOT
+<?xml version="1.0" ?>
+<!DOCTYPE DjVuXML PUBLIC "-//W3C//DTD DjVuXML 1.1//EN" "pubtext/DjVuXML-s.dtd">
+<DjVuXML>
+<HEAD></HEAD>
+<BODY>
+EOT;
+
+		$dump = str_replace( "\r", '', $dump );
+		$line = strtok( $dump, "\n" );
+		$m = false;
+		$good = false;
+		if ( preg_match( '/^( *)FORM:DJVU/', $line, $m ) ) {
+			# Single-page
+			if ( $this->parseFormDjvu( $line, $xml ) ) {
+				$good = true;
+			} else {
+				return false;
+			}
+		} elseif ( preg_match( '/^( *)FORM:DJVM/', $line, $m ) ) {
+			# Multi-page
+			$parentLevel = strlen( $m[1] );
+			# Find DIRM
+			$line = strtok( "\n" );
+			while ( $line !== false ) {
+				$childLevel = strspn( $line, ' ' );
+				if ( $childLevel <= $parentLevel ) {
+					# End of chunk
+					break;
+				}
+
+				if ( preg_match( '/^ *DIRM.*indirect/', $line ) ) {
+					wfDebug( "Indirect multi-page DjVu document, bad for server!\n" );
+
+					return false;
+				}
+				if ( preg_match( '/^ *FORM:DJVU/', $line ) ) {
+					# Found page
+					if ( $this->parseFormDjvu( $line, $xml ) ) {
+						$good = true;
+					} else {
+						return false;
+					}
+				}
+				$line = strtok( "\n" );
+			}
+		}
+		if ( !$good ) {
+			return false;
+		}
+
+		$xml .= "</BODY>\n</DjVuXML>\n";
+
+		return $xml;
+	}
+
+	function parseFormDjvu( $line, &$xml ) {
+		$parentLevel = strspn( $line, ' ' );
+		$line = strtok( "\n" );
+
+		# Find INFO
+		while ( $line !== false ) {
+			$childLevel = strspn( $line, ' ' );
+			if ( $childLevel <= $parentLevel ) {
+				# End of chunk
+				break;
+			}
+
+			if ( preg_match(
+				'/^ *INFO *\[\d*\] *DjVu *(\d+)x(\d+), *\w*, *(\d+) *dpi, *gamma=([0-9.-]+)/',
+				$line,
+				$m
+			) ) {
+				$xml .= Xml::tags(
+					'OBJECT',
+					[
+						# 'data' => '',
+						# 'type' => 'image/x.djvu',
+						'height' => $m[2],
+						'width' => $m[1],
+						# 'usemap' => '',
+					],
+					"\n" .
+						Xml::element( 'PARAM', [ 'name' => 'DPI', 'value' => $m[3] ] ) . "\n" .
+						Xml::element( 'PARAM', [ 'name' => 'GAMMA', 'value' => $m[4] ] ) . "\n"
+				) . "\n";
+
+				return true;
+			}
+			$line = strtok( "\n" );
+		}
+
+		# Not found
+		return false;
+	}
+}